Conventional vehicle seat designs of the type commonly found in the related art typically include a seatback assembly, a lower seat assembly, recliner mechanism, manual or power adjustment mechanism for adjusting a number of positions of either the seatback or lower seat assemblies, as well as a number of safety features including occupant restraint devices such as seatbelts. The seatback assembly also includes a headrest or head restraint that is typically mounted at the top or upper end of the seatback.
In the context of vehicle seating design, there is an ongoing effort to improve the safety of the vehicle occupant in the event of a rear end collision. More specifically, there continues to be an ongoing effort to provide safety mechanisms that reduce the chance of injury in the region of the passengers' neck. In the event of a rear end collision, the occupant is forced against the seat and can experience a large energy pulse. In such circumstances, the pelvis, lumbar, and shoulder or thoracic areas of the occupant can exert force on the seatback, and there is often a separation between the neck and head areas of the occupant and the head restraint. Depending on the force of the rear end collision, this separation can be quickly and violently closed by movement of the upper torso, neck, and head of the passenger toward the seatback in an event commonly known as “whiplash.” Thus, there has been an ongoing effort to address this problem in the context of vehicle seating safety.
In the past, the head restraint was a relatively static device that was typically moveable up and down or slightly tiltable, but usually in connection with adjustments made for the comfort of any given occupant of the seat during normal driving conditions. However, in order to address the problems encountered during a rear end collision, dynamic or active head restraint mechanisms have been proposed in the related art.
For example, U.S. Pat. No. 5,938,279 issued to Schubring et al. and assigned to the assignee of the present invention discloses a dynamic vehicle head restraint assembly that is designed to reduce the amount of separation between the occupant and the head restraint in the event of a rear end collision. The head restraint assembly includes an impact or target plate that is supported by the seatback frame in the general area corresponding to the thoracic or shoulder region of the occupant. The impact plate is pivotally mounted to a linkage that is connected to the head restraint. In the event of a rear end collision, the force of the occupant on the target plate actuates the linkage to cause the head restraint to move toward the head of the occupant, thereby reducing the amount of separation between the occupant and the seatback.
While the dynamic head restraint systems of the type known in the related art were an improvement over the previously known static head restraints, there remains a need in the art to better absorb and dissipate the energy generated by the force acting on the seatback in the event of a rear end collision, especially at the pelvic and lumbar areas, which are generally remote from the head restraint.
U.S. Pat. No. 6,565,150, assigned to the assignee of the present invention, discloses a vehicle seat having an active head restraint that is designed to address this problem. More specifically, the seat has a pivotal support assembly that is mounted to the seatback frame and is operatively connected to the head restraint such that the head restraint moves toward the occupant in the event of a rear end collision. The pivotal support assembly includes a lower impact target that is located in the pelvic and lumbar regions to dissipate the forces that are first translated to the seatback in this area. The lower target is operatively connected to a reaction plate that is pivotally mounted to the seatback. In turn, the head restraint is mounted to the reaction plate.
While the dynamic head restraint systems known in the related art have generally worked for their intended purposes and have improved safety, there remains a need in the art for a vehicle seat assembly that more efficiently and more quickly transfers forces from the occupant to the head restraint system for more effective actuation of the head restraint toward the occupant during a collision. There also remains a need in the art for a vehicle seat assembly with an active head restraint system that is less expensive, lighter, and easier to assemble.